Recursive Call In Palindrome

#1

Mam im unable to understand the recursive Call.Can u please explain me with the code.

#2
  1. If there is only one character in string return true.
  2. Else compare first and last characters and recur for remaining substring.
    see this:
  static boolean isPalRec(String str,  
                            int s, int e) 
    { 
        // If there is only one character 
        if (s == e) 
            return true; 
  
        // If first and last  
        // characters do not match 
        if ((str.charAt(s)) != (str.charAt(e))) 
            return false; 
  
        // If there are more than  
        // two characters, check if 
        // middle substring is also 
        // palindrome or not. 
        if (s < e + 1) 
            return isPalRec(str, s + 1, e - 1); 
  
        return true; 
    }